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Biology Osmosis Lab Report

By bg36fq Aug 01, 2013 2068 Words
Experiment for the measurement of carbon dioxide and oxygen concentrations and their functions during the act of breathing.

Humans, like all living organisms need, O2 in order to live, they take the necessary O2 from the atmospheric air. The O2 is transferred from the blood to all cells of the body and serves for oxidation of nutrients for example glucose. By oxidize the nutrients released energy, which is necessary for the functions of the human body. During oxidation produces CO2, which in high concentrations is harmful to the human body. CO2 is transferred from the blood to the lungs, where is exhales. The intake O2 and the parallel elimination of CO2 in the lungs and is called gas exchange with the environment or otherwise breath (URL1). In physiology respiration is defined as the transport of O2 in the body from the outside air to the cells within tissues and the transport of CO2 in the opposite direction. Thus the basic function of the respiration in human body is to deliver O2 to all parts of the body in order to produce energy for the faction of organism and remove waste product out of this. (URL2). This function is performed by the respiratory system. In the experiment we dealted with breathing and were designed to the chemical factor or factors boost for breath and dealted with the O2 and CO2. Generally in the experiment was four times breathing, different air quality each time, which contains a collection of air from the breathing. Then measure the O2 and CO2 in the air which was collected. At one time was breathing atmospheric air and the other two times was breathing O2 and CO2 respectively. A variety of objects among which the timer for time measurement, mouthpiece for breath, oximeter for measurement the O2 in the blood, a bags for collecting air and two other bag who have O2 and CO2 respectively (URL3). The results were obtained after the recovery gas mixtures were measured in the laboratory through a machine measuring instruments in this gas mixture. The method was used to understand the reasons for which breathing takes place as well as the specific factors causing it. The experiment helped identify these factors by the variations in air intake and exhalation. Using this method we managed to define the ideal air mixture for healthy breathing. Materials and Methods:

A lot has been written and said about the control of respiration in the human body and many textbooks and scholars have dealt with this main issue in medicine. They state that respiration in healthy people is mainly controlled by CO2 concentrations present in the brain and arterial blood. Modern research is focused on specifics and details of this chemical breath control. This experiment recorded the rates of O2 and CO2 concentrations. High levels of CO2 in the blood are naturally poisonous, thus it is preferable to have them at the lowest possible levels. Paradoxically it is the increase of CO2 concentrations which controls breathing in the outer respiration system, the fundamental function of the human body (URL4). At the first stage of the experiment, a person breathed atmospheric air thought a mouthpiece and in order to breathe only from the mouth with the help of the mouthpiece, we used a clip. In this stage of the experiment, breath was taken from normal air which was breathed from room conditions as we all breath daily, with air containing 80% Nitrogen, 20% Oxygen and 0% CO2 . Breathing of normal air was taken for one minute and then the person breathed the air held his holding for as much time as possible and having the nose clip on the nose. He manages to hold his breath 41seconds before he blew out the air blew air into a bag; this moment is called Apnea time. Then the bag was given to the laboratory technician in order to pass the air of the bag passes into a gas analysis. From the analysis of the bag air we have got the percentages of pO2 and pCO2 respectively. The units which provided the resolution are mmHg. In the first analysis, the results were 38, 9 mmHg CO2 and 104, 78 mmHg O2. The second part the experiment was repeated as previously with a few differences. Specifically, with the help of the mouthpiece and the nose clip as before was taken hyperventilation for one minute. Then the breath was hold for as long as possible, namely 61 second, after that pick up the air inside the bag for a gas analyze with the help of the laboratory technician, as before. The percentage of O2 in this case was 102.19 mmHg, while the CO2 was 26 mmHg. In the third part of the experiment we use a special bag containing 5% CO2m, where the mouthpiece was connected with the bag which contained the 5% CO2 and the breathing was taken from the bag for one minute. As previously with the assistant of mouthpiece and nose clip, the breath was hold as long as possible, specifically 37 seconds. Samples of the air in a bag ware taken again as before in the gas analyze to analyze the new rates. The rates which were taken were 111.11 mmHg for O2 and 49 mmHg for CO2. The fourth time the experiment was approximately the same way as the previous times as before; with the difference breathing was taken from a bag containing 40% O2 for one minute, with the help of the mouthpiece. The breath hold was repeated again as long as possible, namely for 52seconds and in this case the rates of the air collected after the gas analyze, were 140.25 mmHg O2 and 55 mmHg CO2. The average of these results was performed in the table below along with the graph. The rates we got were O2 140.25 mmHg and CO2 55 mmHg. In experiment except the mouthpiece and the nose clip used also the oximetre to observe the oxygen present in the body and a stopwatch to measure the time of breath and time of breath holding. Average of these results was performed and the table below along with the graph.


Experiment| Apnoea Time (sec)| Apnoea Time (sec)| pCO2 (mmHg)| pCO2 (mmHg)| pO2 (mmHg)| pO2 (mmHg)| %O2 Saturation| %O2 Saturation| | MEAN| SD| MEAN| SD| MEAN| SD| MEAN| SD|

Normal Air| 59| 9| 38,9| 6,8| 104,78| 20,95| 96| 5| Hyperventilation| 97| 24| 26| 3,9| 102,19| 20,95| 95| 4| 5% CO2| 24| 7| 49| 3| 111,11| 16,13| 96| 3|
40% O2| 86| 9| 55| 3| 140,25| 14,86| 98| 4|

The table records the results of the experiment. Specifically it’s illustrating the average pCO2 (mmHg) and pO2 (mmHg) in the four breaths made during the experiment. On the graph the partial pressures of CO2 and O2 are compared at breaking point in the four different gas mixtures that the subject had to breathe in. The period of time it took the subject to reach breaking point is recorded every time and is otherwise called as apnoea time, as well as the % O2 saturation is recorded with the help of a pulse oxymeter. Observe the table fluctuations of the results depending each time the gas mixtures are changing. In particular we note that the results of pO2 are higher than other prices in contrast to the results of pCO2 which are the lowest. All these variations are due to the increase and decrease of pO2 and pCO2, each time is different and also the need of every organism varies according to its’ needs. The experiment was to breathing four different gases such as exists in the table like Normal air, Hyperventilation, 5% CO2 and 40% O2 for one minute each time. Then follow two graphs with the results of the table we got from the experiment.

The first graph shows the average of pCO2 and pO2. The red line shows the average of the results of pO2 that were collected in the bag. Each dot shows the exact amount of pO2 found after breathing different gas mixtures. The blue line also shows the average results of pCO2 and each dot shows the exact amount of pCO2 found after breathing different gas mixtures. Specifically, we observe that the values of the red line are higher as it should be since we need oxygen to survive. The normal levels of partial pressure of O2 in exhaled air, at rest are 120 mmHg for the oxygen and for carbon dioxide 27 mmHg. However the amounts in the experiment observed are especially different than normal levels because the gas mixture levels of carbon dioxide and oxygen were always different each time and also this is because the breath was held for some time before exhaling. The first point of the graph illustrated decreased rates of oxygen from normal while the rates of carbon dioxide increased. That is due to respiration which continued happening even when the person was holding its breath therefore as there was no rate of elimination and there was no more oxygen breathed in carbon dioxide levels increased since it is a byproduct of respiration. The second point also shows that the amount of pO2 is higher than the amount of pCO2. At this point we had rates from hyperventilation. We see that both the amounts of pO2 and the rate of pCO2 are lower than the previous breath but normal levels. With hyperventilation the oxygen levels are lower from every other condition because the subject is taking short and fast breaths to satisfy it is immediate need for oxygen. Lower amounts of oxygen result to lower amounts of carbon dioxide. The third point shows the rates of respiration when a %5 of CO2 was introduced to the gas mixture. At this point the levels pO2 and pCO2 have increased from the previous breaths. The oxygen levels are reduced compared with the levels of carbon dioxide which is normal since the gas mixture contained 5% of carbon dioxide. Observe these results because at this point there was a large increase in the carbon dioxide resulting in oxygen to be slightly increased because there is a need for the organism to stay at equilibrium levels always so more oxygen uptake was needed. In the fourth section the results are more elevated than all the other points, but in addition is increased and compared to normal levels of exhaled air at rest. The results of this point were obtained after the breathing of 40% more oxygen than normal. With this respiration levels increased since a large amount of oxygen was breathed in and in this way the rate of carbon dioxide increased because is a byproduct of respiration.

In the second graph, the green line shows the % rate of O2 compared to the four times of breathing different gases. Notice that the first and third point at the graph, when the subject was breathing normal air and then when a 5% of CO2 was added to the mixture, are the same amount. I believe that is because both oxygen and carbon dioxide increased as well so the saturation stayed at about normal levels. In hyperventilation it had the smallest percentage of oxygen saturation due to decreased amount of oxygen breathed in. On the other hand, the fourth point has the largest percentage of oxygen breathing because the subject was breathing in a gas mixture that contained 40% more oxygen so it is normal that the oxygen saturation levels are the highest. Conclusion:

This experiment helped us learn how to collect and analyses and expired air samples. They also learn how to appreciate the relative influence of O2 and CO2 on the control of respiration. Floating the aim of the experiment is to determine the risk, chemical and non-chemical, helping to be breathing. So we learned how to find the levels of oxygen and carbon dioxide through the analysis of air. These were made after observation and analysis of the levels of oxygen and carbon dioxide in four different breaths.


URL1: - 9/12/2012 URL2: - 6/12/2012 URL3:

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